This is a prospective, observational study to compare the measurement accuracies of a
wearable loupe-based device and the large microscope against the gold standards of
postoperative histopathological analysis on tumor tissues.
At the induction of anesthesia, patients will receive 5 mg/kg of intravenous sodium
5-aminolevulinic acid (5-ALA) or fluorescein. Surgery will be performed under the
guidance of the operative fluorescence microscope (PENTERO with fluorescence kit + YELLOW
560, Carl Zeiss) or (PENTERO 900 + BLUE 400, Carl Zeiss). The operating room light will
be dimmed for optimum reproduction of the fluorescent light. Tumor removal will be
continued until no fluorescent area is visualized. To evaluate the accuracy of the device
in the identification of tumor tissue, six samples will be biopsied from the tumor
resection margin for each patient; three in the fluorescent area and three in the
non-fluorescent area for the assessment of positive and negative predictive values of the
devices, respectively. These biopsied tissues will be taken to the clinical pathology
laboratory for the standard histological analysis.
To compare the accuracy of the two imaging systems in identifying tumor tissues, the
tumor resection area will be visually observed by the surgeon and video recorded using
the new loupe-based device at two time points (at least): immediately before and
immediately after tumor removal. Additional fluorescence images may be taken during
surgery as long as the surgical workflow is not impacted. Moreover, the four fresh
biopsies (2 in the fluorescent area and 2 in the non-fluorescent area) taken from the
tumor margin based on the operative microscope diagnosis will also be examined
intraoperatively by the loupe-based device to determine whether they are fluorescent or
non-fluorescent.
To discriminate between clear tumor tissue and the peritumoral areas, the postoperative
histological analysis of the biopsied samples taken from the tumor margins will be
classified on the basis of the current 2016 WHO classification. The neuropathologist will
be blinded to the fluorescence characteristics of the biopsied samples.
